1. Field of the Invention
The present invention relates to a surface protein from Bacteroides loeschei which is an adhesin useful in preventing plaque formation in the oral cavity. More specifically, the present invention relates to a purified, characterized adhesin isolated from B. loeschei and its use in a method for preventing or retarding the formation of plaque in the oral cavity as well as other uses based on the binding capabilities of the adhesin.
2. Description of Related Art
The present technologies used to clear microorganisms from the oral cavity rely on non-specific agents to disrupt prior colonization and plaque formation. These agents also pertubate the normal flora which actually protect the hard surfaces in the oral cavity. Such agents include toothpastes, mouthwashes, chewing gum, etc., which all work in a non-specific manner, primarily by means of detergents and abrasives. Thus, it is desirable to obtain a better means for clearing specific unwanted microorganisms from the oral cavity so as to avoid pertubating the normal flora.
Most bacteria isolated from the human oral cavity possess the ability to participate in intergeneric coaggregation, i.e. bacteria from different genera bind to each other primarily via a protein on one attaching to a saccharide component on the other. Coaggregation is characterized by a highly specific binding between stable surface components found on two different bacterial types. Intergeneric coaggregation is thought to play an important role in the formation of dental plaque deposits. Streptococcus sanguis is one of the earliest colonizers of the clean tooth surface and is found in significant numbers in dental plaque. Other primary colonizers of oral hard tissue and the soft tissues of the host (i.e. neuraminidase treated erythrocytes and epithelial cells) include S. oralis and Gamella morbillorum.
Bacteroides loeschei PK1295, a human oral isolate, synthesizes an adhesin which mediates its coaggregation with S. sanguis 34 (Weiss et al, "Fimbria-associated proteins of Bacteroides loeschei PK1295 mediate intergeneric coaggregations," J. Bacteriol., 169, pp. 4215-4222 (1987)) and hemagglutination of a variety of neuraminidase-treated mammalian erythrocytes (Weiss et al, "Fimbria-associated adhesin of Bacteroides loeschei that recognizes receptors on procaryotic and eucaryotic cells," Infect. Immun. 57, pp. 2912-2913 (1989)). Adhesin-specific monoclonal antibodies (MAb) prepared by immunizing mice with adhesin-bearing fimbriae were screened for inhibition of coaggregation (Weiss et al, "Characterization of monoclonal antibodies to fimbria-associated adhesins of Bacteroides loeschei PK1295," Infect. Immun., 56, pp. 219-224 (1988)). Subsequently, the MAbs were used to estimate the number of adhesin molecules per cell and immunoelectron microscopy revealed that the adhesins were associated with the distal portion of the microorganisms fimbriae (Weiss et al, "Localization and enumeration of fimbria-associated adhesins of Bacteroides loeschei," J. Bacteriol., 170, pp. 1123-1128 (1988)). Although some of the coaggregation properties of adhesins from B. loeschei are known, a substantially purified and characterized adhesin has heretofore not been prepared.